//Should we give one dose of the Covid-19 vaccine to more people? The debate, explained.

Should we give one dose of the Covid-19 vaccine to more people? The debate, explained.

In Berlin, people line up to get vaccinated against Covid-19. | Tobias Schwarz/AFP via Getty Images

Britain is delaying the second dose to get more people their first shot. The US isn’t.

In the past couple of weeks, experts and pundits have debated a big question surrounding the rollout of the Covid-19 vaccines from Pfizer/BioNTech and Moderna: Do we stick to two doses for every person, spaced a couple of weeks apart, as was originally planned? Or should we go ahead and give out single doses to more people even when we’re not sure we’ll manage the second dose as planned — to get a shot in as many arms as possible, even if there’s less certainty about the efficacy of that approach?

Britain has taken the latter approach, and much of Europe looks inclined to follow. But the US Food